Automatic mechanical clutch

ABSTRACT

A new and improved automatic mechanical clutch adapted to releasably interconnect two shafts upon a rotation of one of the shafts, and to disconnect such shafts when the rotation of such shaft is discontinued.

United States Patent Slator et al.

1151 3,65l,96 1 51 Mar. 28, 1972 {541 AUTOMATIC MECHANICAL CLUTCH3,194,367 7/1965 Winter 192/16 [72] Inventors: Damon T. Slator; ArchieR. Wilson, both 3,217,847 11/1965 Petrak 192/93 A [73] Assignce: BowenTools, Inc.

Primary ExaminerBen am1n W. Wyche [22] Flledi P 1970 AssistantExaminer-Randall Heald [211 pp No: 25,216 Attorney-Pravel, WllSOl'l &Matthews 57 ABSTRACT 52 us. c1. ..192/35, 192/93 A, 188/83 A new andimproved automatic mechanical clutch adapted to [51] Int. Cl ..F16d43/00 releasably interconnect two Shafts upon a rotation of one of [58]Field of Search 192/35, 36, 93 A, 44 the h ft and to disconnect such h fwhen the rotation f such shaft is discontinued. [56] References Cited 7Claims, 4 Drawing Figures UNITED STATES PATENTS 1,597,198 8/1926 Howell..l92/l08 PATENTEDMRza plume! MaHLewA flTTOR/VE YS AUTOMATIC MECHANICALCLUTCH BACKGROUND OF THE INVENTION The field of this invention isautomatic mechanical clutches.

Various types of mechanical and fluid clutches have been employed in thepast for connecting and disconnecting two shafts. With fluid clutches,the rotation of one shaft acts through the fluid to automatically drivethe other shaft. With mechanical clutches, however, one or more leversor external controls have been used to mechanically engage the clutchfor thereby connecting two shafts or other working parts.

SUMMARY OF THE INVENTION The clutch of the present inventionautomatically connects or disconnects two shafts upon the rotation ornon-rotation, respectively, of one of the shafts, without requiring themanipulation ofa lever or external control by an operator.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation of the clutch ofthis invention, partly in section, illustrating the clutch in a typicalinstallation and in the disengaged position;

FIG. 2 is a vertical sectional view, partly in elevation, taken on line2-2 of FIG. 1 to illustrate further details of the clutch of thisinvention;

FIG. 3 is a horizontal cross-sectional view taken on line 3 3 ofFIG. 2;and

FIG. 4 is an elevation of the clutch of this invention in the engagedposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, letter Adesignates generally the automatic mechanical clutch ofthis inventionwhich has clutch elements C and Cl which are connected with shafts S and8-1, respectively, in a manner to be hereinafter described. As will beexplained in detail, upon a rotation of the shaft S a predeterminedamount in either direction, the clutch elements C and C-] are engaged soas to transmit further rotation of the shaft S through the clutchelements C and C-1 to the shaft S-l. Upon discontinuing the rotation ofthe shaft S, the clutch elements C and C-1 are automatically disengagedso that the shaft S-1 can thereafter be rotated independently of theshaft S.

Considering the invention more in detail, the shaft S-l is connnected tothe clutch elements C-l by a suitable key 10 (FIG. 2), or any othersuitable connecting means so that rotation of the shaft 8-1 istransmitted to the clutch element C-1, and vice versa. The shaft S-l maybe suitably supported in any conventional bearing 12 which is mounted ona frame 14 or other suitable support. The shaft S-1 may be driven orrotated by any suitable source of power connected through a chain (notshown) to a sprocket 15 which is mounted on the shaft S- 1. As will beexplained hereinafter, the engagement of the clutch A can be effected atany relative rotational position of the clutch elements C and C-1, andonce the clutch A is engaged, the shaft 5-1 is then driven by the shaftS so as to overpower any driving force exerted on the shaft S-l throughthe sprocket drive 15.

The shaft S is mounted in a suitable bearing 16 which is mounted on aframe 14' which may be a part of the same structure as the frame 14.

The shaft S extends upwardly into the interior bore 18 ofthe clutchelement C, but it terminates short ofthe clutch teeth 20 on the clutchelement C. It is to be noted that the clutch element C-l has clutchteeth 120 which correspond with the clutch teeth 20 so that they caninterfit with each other for engagement and for a locked drivingconnection between such elements C and C-1, as will be more fullyexplained in connection with FIG. 4.

The clutch element C has essentially a cylindrical body 21 which isformed with one, and preferably two, cam slots 22,

each of which is adapted to receive a cam pin 23 which is suitablysecured to the shaft 8 and is movable therewith. Each cam slot 22 isformed with an upper cam surface which has a mid-point 22a which iscloser to the clutch teeth 20 than the rest of the cam surface of theslot 22. The legs or sides 22b of the cam surface of the slot 22 areinclined downwardly and away from the mid-point 22a so that when the campin 23 is moved rotationally relative to the cam slot 22, it rides onone of the cam surfaces 22b from the mid-point 22a to impart alongitudinal movement to the clutch element C relative to the shaft S.Such longitudinal movement of the clutch element C is sufficient to movethe clutch element C from the disengaged position (FIGS. 1 and 2) to theengaged position (FIG. 4).

A coil spring 30, or other suitable resilient means is confined betweenthe cam pin 23 and a retaining shoulder 21a in the body 21 of the clutchelement C. Such spring 30 is preferably positioned under slightcompression at all times so that it acts to urge the pin 23 and theshaft S therewith in a longitudinal direction relative to the clutchelement C towards the clutch teeth 20. Such urging maintains the uppersurface of the pin 23 in engagement with the upper cam surface of thecam slot 22 as viewed in FIGS. 1 and 2, at all times. When the pin 23moves from the mid-point 22a to the extremity on either side of the slot22, the clutch element C is moved upwardly relative to the shaft S asviewed in FIGS. 1 and 2 and such movement causes an increase in thecompression of the spring 30 since it is confined between the pin 23 andthe shoulder 21a.

A holding means H is provided for coaction with the clutch element C toprevent the element C from rotating until the cam pin 23 has reached itsextremity at either end of the cam slot 22, at which time the holdingmeans H is releasable for enabling the clutch element C to move with theshaft S as it is rotated. The holding means H is preferably made withone or more engaging members or balls 50 which are disposed in radialopenings 51a in a ring 51.

The ring 51 is fixed to a frame such as the frame member 14 through aconnector 52 (FIG. 1) so that the ring 51 does not rotate. Although thenumber of holes or slots 51a in the ring 51 may vary, it is preferableto provide three of such slots for receiving three holding balls 50.Each of the balls 50 is urged radially inwardly towards the clutchelement body 21 by a coil spring 55, or other suitable resilient means.Each spring 55 is releasably confined under compression against one ofthe balls 50 by a retaining screw 56 which is suitably threaded into thering 51 The inner end of each slot 510 is preferably curved as indicatedat 51b so as to limit the extent of inward movement of each ball 50 sothat the balls 50 are not forced out of the openings 51a due to thespring pressure of the springs 55 thereon.

The external lower surface of the clutch element C is formed with aplurality of flat surfaces 21b, which are preferably six in number, andwhich surfaces 21b are adapted to be engaged by one of the balls 50 forexerting a holding force on the clutch element C. However, when asufficient rotational force is exerted on the clutch element C by theshaft S when the pin or pins 23 reach the extremity of the cam slot orslots 22 in one direction, the balls 50 are forced outwardly against thesprings 55 so as to permit the clutch element C to rotate with the shaftS.

In the operation of the clutch A of this invention, the shaft 8-1 isfree-wheeling, i.e., it is free to rotate or be rotated independently ofthe shaft S when the clutch A is disengaged. However, when it isdesirable to drive the shaft S-l so as to control its rotation, it isaccomplished by rotating the shaft 5 either manually or mechanically ineither direction, depending upon the direction of rotation desired forthe shaft 8-1. The clutch A is automatically engaged after apredetermined amount of rotation of the shaft S, and it is automaticallydisengaged upon a discontinuing of the rotation of the shaft S.

Thus, the spring 30 holds the cam pin 23 in the upper position shown inFIGS. 1 and 2 so as to normally hold the clutch teeth 20 and apart fromeach other, whereby the clutch elements C and C-1 are disengaged fromeach other. Such condition exists so long as the pin 23 remains atsubstantially the mid-portion or point 22a of the slot or slots 22. Suchlocation of the pin 23 remains at the mid-point 22a so long as the shaftS is stationary with respect to the clutch element C. While the shaft Sis stationary and the clutch teeth and 120 are disengaged from eachother, the shaft 8-] is free to rotate independently of the shaft S, andit may be rotated through any suitable means such as by engagement withthe drive sprocket 15.

Upon a rotation of the shaft S in one rotational direction, the clutchelement C is held initially to prevent its rotation with the shaft S.The holding is accomplished through the holding means H due to thespring pressed balls 50 which are in engagement with the plurality offlat surfaces 21b of the clutch element C. Because the clutch element Cis thus held initially against rotation, the cam pin or pins 23 moverelative to the clutch element C along the cam surfaces provided at theupper end of the cam slots 22. Since the shaft S is mounted on the fixedframe 14 or other suitable support or frame, the movement of the shaft Scauses a camming or longitudinal movement of the clutch element Clongitudinally upwardly as viewed in FIGS. 1 and 2 which is in adirection to cause the teeth 20 and 120 to engage with each other.Should the teeth 20 and 120 be so misaligned that the teeth on one ofthe clutch elements cannot interfit with the teeth on the other of theclutch elements, the teeth 20 and 120 will contact each other enough sothat a driving force is exerted from the cam pin or pins 23 to theclutch element C to overcome the pressure of the balls 50 and to thusrotate the clutch element C with the shaft S. Such rotation occurs foronly a relatively short distance before the teeth 20 and 120 are alignedso that they can interfit with each other, at which time, the cam pin 23may go all of the way to the end ofits cam slot 22, thus forcing theclutch element C to the fully engaged position shown in FIG. 4.

Of course, if the teeth 20 and 120 are aligned at the time the shaft Sis initially rotated, the pin 23 will move to one end of the slot 22prior to any rotation of the clutch element C, so that the clutch teeth20 and 120 become interengaged and locked with each other beforerotation of the clutch element C occurs.

After the clutch teeth 20 and 120 have become connected, the continuedrotation of the shaft S in the same direction is transmitted through thecam pin 23 to the clutch element C and thus to the clutch element C-l soas to transmit the rotation ofthe shaft S to the shaft 8-1.

When the shaft S is stopped, the spring acts to return the clutchelement C downwardly by causing the cam surface 22b to ride along thecam pin 23 until the cam pin 23 has reached the mid-point 22a, at whichtime the teeth 20 and 120 are fully disengaged (FIG. 1).

It is to be noted that the cam 22 is provided with two oppositelyinclined cam surfaces 22b which diverge downwardly from the mid-point22a so as to accomplish an engagement of the clutch elements C and C-1upon a rotation of the shaft S in either direction. It will beappreciated that only one-half of each cam slot 22 may be utilized, inwhich case, the clutch A would be engaged in only one rotationaldirection of the shaft The foregoing disclosure and description of theinvention are illustrative and explanatory thereof, and various changesin the size, shape, and materials as well as in the details of theillustrated construction may be made without departing from the spiritof the invention.

In the claims:

1. An automatic mechanical clutch adapted to connect and disconnect twoshafts, comprising:

a first clutch element fixed on a first shaft for rotation together; asecond clutch element mounted on a second shaft for limited rotationalmovement relative to each other;

means for urging said clutch elements apart to a disengaged positionwhen said second shaft is substantially stationary with respect to saidsecond clutch element;

actuating means for moving said second clutch element into operableengagement with said first clutch in response to a predetermined amountof rotation of said second shaft relative to said second clutch elementand for thereafter transmitting rotation of said second shaft throughsaid engaged clutch elements to said first shaft; and

releasable holding means for releasably holding said second clutchelement against rotation until a predetermined torque is applied theretofrom said shaft.

2. The structure set forth in claim 1, wherein said means for urgingsaid clutch elements apart acts to return said clutch elements to thedisengaged position when the rotation of said second shaft isdiscontinued.

3. The structure set forth in claim 1, wherein said means for urgingsaid clutch elements apart includes:

a spring; and

means on said clutch element and said second shaft for confining saidspring and compressing it upon a rotation of said second shaft relativeto said second clutch element.

4. The structure set forth in claim 1, wherein said holding meansincludes:

a plurality of flat surfaces on the external surface of said secondclutch element; and

a spring pressed ball resiliently engaging one of said flat surfaces.

5. The structure set forth in claim 1, wherein said actuating meansincludes:

a cam guide surface formed in said second clutch element;

and

a cam pin on said second shaft extending into engagement with said camguide surface for following same to effect a longitudinal movement ofsaid second clutch element relative to said second shaft an said firstclutch element.

6. The structure set forth in claim 5, wherein:

said cam guide surface extends laterally and is formed with two legswhich are inclined towards each other to a midpoint which is displacedlongitudinally closer to said first clutch element than the rest of saidcam guide surface.

7. The structure set forth in claim 1, wherein:

said clutch elements have clutch teeth which interfit to lock saidclutch elements together when they are moved into interfittingengagement.

1. An automatic mechanical clutch adapted to connect and disconnect twoshafts, comprising: a first clutch element fixed on a first shaft forrotation together; a second clutch element mounted on a second shaft forlimited rotational movement relative to each other; means for urgingsaid clutch elements apart to a disengaged position when said secondshaft is substantially stationary with respect to said second clutchelement; actuating means for moving said second clutch element intooperable engagement with said first clutch-element in response to apredetermined amount of rotation of said second shaft relative to saidsecond clutch element and for thereafter transmitting rotation of saidsecond shaft through said engaged clutch elements to said first shaft;and releasable holding means for releasably holding said second clutchelement against rotation until a predetermined torque is applied theretofrom said shaft.
 2. The structure set forth in claim 1, wherein saidmeans for urging said clutch elements apart acts to return said clutchelements to the disengaged position when the rotation of said secondshaft is discontinued.
 3. The structure set forth in claim 1, whereinsaid means for urging said clutch elements apart includes: a spring; andmeans on said clutch element and said second shaft for confining saidspring and compressing it upon a rotation of said second shaft relativeto said second clutch element.
 4. The structure set forth in claim 1,wherein said holding means includes: a plurality of flat surfaces on theexternal surface of said second clutch element; and a spring pressedball resiliently engaging one of said flat surfaces.
 5. The structureset forth in claim 1, wherein said actuating means includes: a cam guidesurface formed in said second clutch element; and a cam pin on saidsecond shaft extending into engagement with said cam guide surface forfollowing same to effect a longitudinal movement of said second clutchelement relative to said second shaft an said first clutch element. 6.The structure set forth in claim 5, wherein: said cam guide surfaceextends laterally and is formed with two legs which are inclined towardseach other to a mid-point which is displaced longitudinally closer tosaid first clutch element than the rest of said cam guide surface. 7.The structure set forth in claim 1, wherein: said clutch elements haveclutch teeth which interfit to lock said clutch elements together whenthey are moved into interfitting engagement.